Introduction¶
This document describes the analysis that took place before writing the final report.
Loading dependencies¶
In [1]:
# loading libraries
from sklearn.datasets import load_files
from sklearn.model_selection import train_test_split
from sklearn.metrics import confusion_matrix, f1_score
import numpy as np
from keras.utils import np_utils
from glob import glob
import matplotlib.pyplot as plt
import matplotlib.image as mpimg
from PIL import Image
%matplotlib inline
import seaborn as sns
from keras.preprocessing import image
from keras.preprocessing.image import ImageDataGenerator, array_to_img, img_to_array, load_img
from keras.layers import Conv2D, MaxPooling2D, Dropout, Flatten, Dense, GlobalAveragePooling2D
from keras.layers import GlobalMaxPooling2D, Input, Activation
from keras.layers.normalization import BatchNormalization
from keras.models import Sequential, Model
from keras.callbacks import ModelCheckpoint
from keras import backend as K
from keras.applications.vgg16 import VGG16
from keras.applications.vgg19 import VGG19
from keras.applications.resnet50 import ResNet50
from keras.applications.inception_v3 import InceptionV3
from keras.preprocessing import image
from keras.applications.vgg19 import preprocess_input
from keras import optimizers
from keras.regularizers import l2
from tqdm import tqdm
import os
import random
import shutil
import itertools
import pandas as pd
Loading data¶
In [2]:
# loading data
data = load_files('/seedlings-data/train', load_content=False, shuffle=False)
print(f"There are {len(data['target_names'])} categories")
print (f"These categories are {data['target_names']}")
print (f"There are {len(data['filenames'])} images in training dataset")
Visualizations¶
In [3]:
"""
Show 5 samples of each plant species
Each image's title is its filename. Each image's subtitle is it's height and width in pixels.
"""
def display_sample_images(n=5):
for seedling_id in range(len(data['target_names'])):
fig = plt.figure(figsize=(20,5))
fig.suptitle(data['target_names'][seedling_id], fontsize=32)
img_list = [i for i, j in enumerate(data['target']) if j == seedling_id]
for i in range(n):
seedling_file = data['filenames'][img_list[i]]
filename = seedling_file[-13:-4]
with Image.open(seedling_file) as img:
ax = fig.add_subplot(1, n, i+1, xticks=[], yticks=[])
ax.set_title(filename)
ax.set_xlabel("Size: %d X %d " % (img.size[0], img.size[1]))
ax.imshow(mpimg.imread(seedling_file))
plt.show()
display_sample_images()
Splitting data into train and test set¶
In [4]:
"""
Spliting data into a training and a testing set.
"""
def split_data_train_and_test(data, test_section = 0.1):
x = np.array(data['filenames'])
y = np.array(data['target'])
x_train, x_test, y_train, y_test = train_test_split(x, y, test_size=test_section, random_state=0)
return x_train, x_test, y_train, y_test
x_train, x_test, y_train, y_test = split_data_train_and_test(data)
One hot encoding targets¶
In [5]:
"""
Targets are one-hot-encoded by converting them from integers to vectors with a length
equal to the number of plant species
"""
y_train_targets = np_utils.to_categorical(y_train, len(data['target_names']))
y_test_targets = np_utils.to_categorical(y_test, len(data['target_names']))
Plot the plant distribution¶
In [6]:
"""
Plot the distribution of samples across all plant species
"""
def plot_class_distribution(targets, ylim):
labels = np.array(data['target_names'])
fig, ax = plt.subplots()
x_pos = np.arange(len(labels))
train_labels = np.sum(targets, axis=0)
ax.bar(x_pos, train_labels, align='center')
ax.set_ylim(0, ylim)
plt.xticks(x_pos, labels, rotation='vertical')
plt.xlabel("Plant species")
plt.ylabel("Number of samples")
plt.show()
sns.set(color_codes=True)
plot_class_distribution(y_train_targets, 600)
plot_class_distribution(y_test_targets, 100)
Images to tensors¶
In [7]:
def path_to_tensor(img_path):
# loads RGB image as PIL.Image.Image type
img = image.load_img(img_path, target_size=(224, 224))
# convert PIL.Image.Image type to 3D tensor with shape (224, 224, 3)
x = image.img_to_array(img)
# convert 3D tensor to 4D tensor with shape (1, 224, 224, 3) and return 4D tensor
return np.expand_dims(x, axis=0)
def paths_to_tensors(img_paths):
list_of_tensors = [path_to_tensor(img_path) for img_path in tqdm(img_paths)]
return np.vstack(list_of_tensors)
In [8]:
# Create the tensors from x_train and x_test
x_train_tensors = paths_to_tensors(x_train)
x_test_tensors = paths_to_tensors(x_test)
Augmenting data¶
The data augmentation I used was based on https://machinelearningmastery.com/image-augmentation-deep-learning-keras/ and https://blog.keras.io/building-powerful-image-classification-models-using-very-little-data.html and https://arxiv.org/pdf/1712.04621.pdf
In [9]:
datagen = ImageDataGenerator(
rotation_range=40,
width_shift_range=0.2,
height_shift_range=0.2,
shear_range=0.2,
zoom_range=0.2,
horizontal_flip=True,
fill_mode='nearest')
In [10]:
def empty_augmented_data_directory(path):
if os.path.isdir(path):
shutil.rmtree(path)
os.makedirs(path)
def image_augmentation(x_train_tensors, y_train, labels, batch_size):
path = '/output/augmented_images'
empty_augmented_data_directory(path)
for seedling_id in range(len(data['target_names'])):
target_dir = '%s/%s' % (path, labels[seedling_id])
os.makedirs(target_dir)
images = [i for i, j in enumerate(y_train) if j == seedling_id]
random.shuffle(images)
images = (images * (batch_size // len(images))) + images[0:batch_size % len(images)]
n_images = x_train_tensors[images]
for batch in datagen.flow(n_images, batch_size=batch_size, save_to_dir=target_dir, save_format='png'):
break
In [11]:
# The augmented data only needs to be created once. As it takes a long time to create
# and I pay floydhub.com by the minute the following line is commented out.
#image_augmentation(x_train_tensors, y_train, np.array(data['target_names']), 2500)
In [12]:
# The augmented_images were downloaded and uploaded back to floydhub as a dataset
augmented_data = load_files('/augmented_images', load_content=False, shuffle=False)
print (f"There are {len(augmented_data['filenames'])} images in training dataset")
In [13]:
# Naturally the augmented images have to be tensorized and hot_encoded also
x_augmented = np.array(augmented_data['filenames'])
x_augmented_tensors = paths_to_tensors(x_augmented)
y_augmented = np.array(augmented_data['target'])
y_augmented_targets = np_utils.to_categorical(y_augmented, len(data['target_names']))
In [14]:
# plotting the augmented data
sns.set(color_codes=True)
plot_class_distribution(y_augmented_targets, 3000)
Calculating f1 score¶
For reasons unclear to me F1 is not offered as a metric in Keras. Fortunately my good friends Google and Stackoverflow know everything The code below comes from stackoverflow
In [15]:
def f1(y_true, y_pred):
def recall(y_true, y_pred):
"""Recall metric.
Only computes a batch-wise average of recall.
Computes the recall, a metric for multi-label classification of
how many relevant items are selected.
"""
true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1)))
possible_positives = K.sum(K.round(K.clip(y_true, 0, 1)))
recall = true_positives / (possible_positives + K.epsilon())
return recall
def precision(y_true, y_pred):
"""Precision metric.
Only computes a batch-wise average of precision.
Computes the precision, a metric for multi-label classification of
how many selected items are relevant.
"""
true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1)))
predicted_positives = K.sum(K.round(K.clip(y_pred, 0, 1)))
precision = true_positives / (predicted_positives + K.epsilon())
return precision
precision = precision(y_true, y_pred)
recall = recall(y_true, y_pred)
return 2*((precision*recall)/(precision+recall+K.epsilon()))
Training method¶
In [16]:
"""
Train a model.
Parameters:
model: The model to train.
x: x_train_tensors or x_augmented_tensors.
y: y_train_targets or y_augmented_targets.
epochs: Number of epochs
"""
def train_model(model, x, y, epochs):
checkpointer = ModelCheckpoint(filepath=f"/output/weights.best.from_{model.name}.hdf5",
verbose=1, save_best_only=True)
model.fit(x, y, validation_data=(x_test_tensors, y_test_targets),
epochs=epochs, batch_size=20, callbacks=[checkpointer], verbose=1)
Evaluation functions¶
In [17]:
"""
This code comes from the scikit-learn documentation
http://scikit-learn.org/stable/auto_examples/model_selection/plot_confusion_matrix.html
"""
def plot_confusion_matrix(cm, classes,
normalize=False,
title='Confusion matrix',
cmap=plt.cm.Blues):
"""
This function prints and plots the confusion matrix.
Normalization can be applied by setting `normalize=True`.
"""
if normalize:
cm = cm.astype('float') / cm.sum(axis=1)[:, np.newaxis]
print("Normalized confusion matrix")
else:
print('Confusion matrix, without normalization')
#print(cm)
plt.imshow(cm, interpolation='nearest', cmap=cmap)
plt.title(title)
plt.colorbar()
tick_marks = np.arange(len(classes))
plt.xticks(tick_marks, classes, rotation=45)
plt.yticks(tick_marks, classes)
fmt = '.2f' if normalize else 'd'
thresh = cm.max() / 2.
for i, j in itertools.product(range(cm.shape[0]), range(cm.shape[1])):
plt.text(j, i, format(cm[i, j], fmt),
horizontalalignment="center",
color="white" if cm[i, j] > thresh else "black")
plt.tight_layout()
plt.ylabel('True label')
plt.xlabel('Predicted label')
In [18]:
"""
Evaluate the results of a model. Displaying confusion matrix (normalized and not not normalized) and F1 score
"""
def evaluate_model(model):
model.load_weights(f"/output/weights.best.from_{model.name}.hdf5")
y_pred = [np.argmax(model.predict(np.expand_dims(tensor, axis=0))) for tensor in x_test_tensors]
y_test = np.argmax(y_test_targets, axis=1)
# Compute confusion matrix
cnf_matrix = confusion_matrix(y_test, y_pred)
np.set_printoptions(precision=2)
# Plot non-normalized confusion matrix
plt.figure(figsize=(20,10))
class_names = np.array(data['target_names'])
plot_confusion_matrix(cnf_matrix, classes=class_names,
title='Confusion matrix, without normalization')
# Plot normalized confusion matrix
plt.figure(figsize=(15,10))
plot_confusion_matrix(cnf_matrix, classes=class_names, normalize=True,
title='Normalized confusion matrix')
plt.show()
f1 = f1_score(y_test, y_pred, average='micro')
print(f"{model.name} F1 Score: {f1}")
In [19]:
def train_and_evaluate(model, x, y, epochs):
train_model(model, x, y, epochs)
evaluate_model(model)
Defining a homemade CNN¶
Starting with the same model I used on the dog classifier project
In [20]:
def create_basic_model():
basic_model = Sequential()
basic_model.name = 'basic_model'
basic_model.add(Conv2D(filters=16,kernel_size=2,strides=1,activation='relu',input_shape=x_train_tensors[0].shape))
basic_model.add(MaxPooling2D(pool_size=2,strides=2))
#basic_model.add(Dropout(0.33))
basic_model.add(Conv2D(filters=32, kernel_size=2,strides=1,activation='relu'))
basic_model.add(MaxPooling2D(pool_size=2,strides=2))
#basic_model.add(Dropout(0.33))
basic_model.add(Conv2D(filters=64, kernel_size=2,strides=1,activation='relu'))
basic_model.add(MaxPooling2D(pool_size=2,strides=2))
#basic_model.add(Dropout(0.33))
basic_model.add(Conv2D(filters=128, kernel_size=2,strides=1,activation='relu'))
basic_model.add(MaxPooling2D(pool_size=2,strides=2))
basic_model.add(Conv2D(filters=256, kernel_size=2,strides=1,activation='relu'))
basic_model.add(MaxPooling2D(pool_size=2,strides=2))
basic_model.add(GlobalAveragePooling2D())
basic_model.add(Dense(len(data['target_names']),activation='softmax'))
basic_model.summary()
basic_model.compile(loss="categorical_crossentropy", optimizer= "adam", metrics=[f1])
return basic_model
VGG-16¶
Inspired by this medium article
In [21]:
def create_vgg16_model():
vgg_start_model = VGG16(weights='imagenet', include_top=False, input_shape=x_train_tensors[0].shape)
vgg_start_model.layers.pop()
vgg_start_model.layers.pop()
vgg_start_model.layers.pop()
vgg_start_model.outputs = [vgg_start_model.layers[-1].output]
vgg_start_model.layers[-2].outbound_nodes= []
x=Conv2D(256, kernel_size=(2,2),strides=2)(vgg_start_model.output)
x = BatchNormalization()(x)
x = Activation('relu')(x)
x=Conv2D(128, kernel_size=(2,2),strides=1)(x)
x = BatchNormalization()(x)
x = Activation('relu')(x)
x=Flatten()(x)
x=Dense(len(data['target_names']), activation='softmax')(x)
VGG16_model=Model(vgg_start_model.input,x)
for layer in VGG16_model.layers[:15]:
layer.trainable = False
VGG16_model.compile(optimizer='adam', loss='categorical_crossentropy', metrics=[f1])
return VGG16_model
In [22]:
def create_vgg19_model():
vgg_start_model = VGG19(weights='imagenet', include_top=False, input_shape=x_train_tensors[0].shape)
vgg_start_model.layers.pop()
vgg_start_model.layers.pop()
vgg_start_model.layers.pop()
vgg_start_model.outputs = [vgg_start_model.layers[-1].output]
vgg_start_model.layers[-2].outbound_nodes= []
x=Conv2D(256, kernel_size=(2,2),strides=2)(vgg_start_model.output)
x = BatchNormalization()(x)
x = Activation('relu')(x)
x=Conv2D(128, kernel_size=(2,2),strides=1)(x)
x = BatchNormalization()(x)
x = Activation('relu')(x)
x=Flatten()(x)
x=Dense(len(data['target_names']), activation='softmax')(x)
VGG19_model=Model(vgg_start_model.input,x)
for layer in VGG19_model.layers[:15]:
layer.trainable = False
VGG19_model.compile(optimizer='adam', loss='categorical_crossentropy', metrics=[f1])
return VGG19_model
ResNet50¶
In [23]:
def create_resnet50_model():
resnet_start_model = ResNet50(weights = "imagenet", include_top=False, input_shape=x_train_tensors[0].shape)
# Add custom layers
x = resnet_start_model.output
x = Flatten()(x)
predictions = Dense(len(data['target_names']), activation='softmax')(x)
# Creating the ResNet50 model
ResNet50_model = Model(input = resnet_start_model.input, output = predictions)
ResNet50_model.name = 'resnet50_model'
ResNet50_model.summary()
ResNet50_model.compile(optimizer=optimizers.SGD(lr=0.0001, momentum=0.9), loss='categorical_crossentropy', metrics=[f1])
return ResNet50_model
Train and evaluate the models¶
In [24]:
#basic_model = create_basic_model()
#train_and_evaluate(basic_model, x_train_tensors, y_train_targets, 20)
#train_and_evaluate(basic_model, x_augmented_tensors, y_augmented_targets, 20)
#VGG16_model = create_vgg16_model()
#train_and_evaluate(VGG16_model, x_train_tensors, y_train_targets, 5)
#train_and_evaluate(VGG16_model, x_augmented_tensors, y_augmented_targets, 10)
#VGG19_model = create_vgg19_model()
#train_and_evaluate(VGG19_model, x_train_tensors, y_train_targets, 5)
#train_and_evaluate(VGG19_model, x_augmented_tensors, y_augmented_targets, 10)
ResNet50_model = create_resnet50_model()
#train_and_evaluate(ResNet50_model, x_train_tensors, y_train_targets, 10)
train_and_evaluate(ResNet50_model, x_augmented_tensors, y_augmented_targets, 10)
Prepare submission to Kaggle¶
In [25]:
"""
Prepare the csv file with predictions for the unlabeled data for submission to Kaggle
"""
def create_prediction_for_kaggle(model):
# loading data
unlabeled_data = glob('/seedlings-data/test/*')
unlabeled_tensors = paths_to_tensors(unlabeled_data)
prediction = [np.argmax(model.predict(np.expand_dims(tensor, axis=0))) for tensor in unlabeled_tensors]
labels = np.array(data['target_names'])
file_names = [x[15:] for x in unlabeled_data]
df = pd.DataFrame(index=file_names, data=labels[prediction])
df.to_csv(f"/output/prediction_from_{model.name}.csv")
In [26]:
#create_prediction_for_kaggle(basic_model)
create_prediction_for_kaggle(ResNet50_model)